/*
 *  Public Key abstraction layer
 *
 *  Copyright The Mbed TLS Contributors
 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 *
 *  This file is provided under the Apache License 2.0, or the
 *  GNU General Public License v2.0 or later.
 *
 *  **********
 *  Apache License 2.0:
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  **********
 *
 *  **********
 *  GNU General Public License v2.0 or later:
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 *  **********
 */

#if !defined(MBEDTLS_CONFIG_FILE)
#include "nettls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#if defined(MBEDTLS_PK_C)
#include "nettls/pk.h"
#include "nettls/pk_internal.h"

#include "nettls/platform_util.h"

#if defined(MBEDTLS_RSA_C)
#include "nettls/rsa.h"
#endif
#if defined(MBEDTLS_ECP_C)
#include "nettls/ecp.h"
#endif
#if defined(MBEDTLS_ECDSA_C)
#include "nettls/ecdsa.h"
#endif

#include <limits.h>
#include <stdint.h>

/* Parameter validation macros based on platform_util.h */
#define PK_VALIDATE_RET(cond) MBEDTLS_INTERNAL_VALIDATE_RET(cond, MBEDTLS_ERR_PK_BAD_INPUT_DATA)
#define PK_VALIDATE(cond)     MBEDTLS_INTERNAL_VALIDATE(cond)

/*
 * Initialise a mbedtls_pk_context
 */
void mbedtls_pk_init(mbedtls_pk_context* ctx)
{
    PK_VALIDATE(ctx != NULL);

    ctx->pk_info = NULL;
    ctx->pk_ctx = NULL;
}

/*
 * Free (the components of) a mbedtls_pk_context
 */
void mbedtls_pk_free(mbedtls_pk_context* ctx)
{
    if (ctx == NULL)
        return;

    if (ctx->pk_info != NULL)
        ctx->pk_info->ctx_free_func(ctx->pk_ctx);

    mbedtls_platform_zeroize(ctx, sizeof(mbedtls_pk_context));
}

#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
/*
 * Initialize a restart context
 */
void mbedtls_pk_restart_init(mbedtls_pk_restart_ctx* ctx)
{
    PK_VALIDATE(ctx != NULL);
    ctx->pk_info = NULL;
    ctx->rs_ctx = NULL;
}

/*
 * Free the components of a restart context
 */
void mbedtls_pk_restart_free(mbedtls_pk_restart_ctx* ctx)
{
    if (ctx == NULL || ctx->pk_info == NULL || ctx->pk_info->rs_free_func == NULL) {
        return;
    }

    ctx->pk_info->rs_free_func(ctx->rs_ctx);

    ctx->pk_info = NULL;
    ctx->rs_ctx = NULL;
}
#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */

/*
 * Get pk_info structure from type
 */
const mbedtls_pk_info_t* mbedtls_pk_info_from_type(mbedtls_pk_type_t pk_type)
{
    switch (pk_type) {
#if defined(MBEDTLS_RSA_C)
    case MBEDTLS_PK_RSA:
        return (&mbedtls_rsa_info);
#endif
#if defined(MBEDTLS_ECP_C)
    case MBEDTLS_PK_ECKEY:
        return (&mbedtls_eckey_info);
    case MBEDTLS_PK_ECKEY_DH:
        return (&mbedtls_eckeydh_info);
#endif
#if defined(MBEDTLS_ECDSA_C)
    case MBEDTLS_PK_ECDSA:
        return (&mbedtls_ecdsa_info);
#endif
    /* MBEDTLS_PK_RSA_ALT omitted on purpose */
    default:
        return (NULL);
    }
}

/*
 * Initialise context
 */
int mbedtls_pk_setup(mbedtls_pk_context* ctx, const mbedtls_pk_info_t* info)
{
    PK_VALIDATE_RET(ctx != NULL);
    if (info == NULL || ctx->pk_info != NULL)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);

    if ((ctx->pk_ctx = info->ctx_alloc_func()) == NULL)
        return (MBEDTLS_ERR_PK_ALLOC_FAILED);

    ctx->pk_info = info;

    return (0);
}

#if defined(MBEDTLS_PK_RSA_ALT_SUPPORT)
/*
 * Initialize an RSA-alt context
 */
int mbedtls_pk_setup_rsa_alt(
    mbedtls_pk_context* ctx,
    void* key,
    mbedtls_pk_rsa_alt_decrypt_func decrypt_func,
    mbedtls_pk_rsa_alt_sign_func sign_func,
    mbedtls_pk_rsa_alt_key_len_func key_len_func)
{
    mbedtls_rsa_alt_context* rsa_alt;
    const mbedtls_pk_info_t* info = &mbedtls_rsa_alt_info;

    PK_VALIDATE_RET(ctx != NULL);
    if (ctx->pk_info != NULL)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);

    if ((ctx->pk_ctx = info->ctx_alloc_func()) == NULL)
        return (MBEDTLS_ERR_PK_ALLOC_FAILED);

    ctx->pk_info = info;

    rsa_alt = (mbedtls_rsa_alt_context*)ctx->pk_ctx;

    rsa_alt->key = key;
    rsa_alt->decrypt_func = decrypt_func;
    rsa_alt->sign_func = sign_func;
    rsa_alt->key_len_func = key_len_func;

    return (0);
}
#endif /* MBEDTLS_PK_RSA_ALT_SUPPORT */

/*
 * Tell if a PK can do the operations of the given type
 */
int mbedtls_pk_can_do(const mbedtls_pk_context* ctx, mbedtls_pk_type_t type)
{
    /* A context with null pk_info is not set up yet and can't do anything.
     * For backward compatibility, also accept NULL instead of a context
     * pointer. */
    if (ctx == NULL || ctx->pk_info == NULL)
        return (0);

    return (ctx->pk_info->can_do(type));
}

/*
 * Helper for mbedtls_pk_sign and mbedtls_pk_verify
 */
static inline int pk_hashlen_helper(mbedtls_md_type_t md_alg, size_t* hash_len)
{
    const mbedtls_md_info_t* md_info;

    if (*hash_len != 0)
        return (0);

    if ((md_info = mbedtls_md_info_from_type(md_alg)) == NULL)
        return (-1);

    *hash_len = mbedtls_md_get_size(md_info);
    return (0);
}

#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
/*
 * Helper to set up a restart context if needed
 */
static int pk_restart_setup(mbedtls_pk_restart_ctx* ctx, const mbedtls_pk_info_t* info)
{
    /* Don't do anything if already set up or invalid */
    if (ctx == NULL || ctx->pk_info != NULL)
        return (0);

    /* Should never happen when we're called */
    if (info->rs_alloc_func == NULL || info->rs_free_func == NULL)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);

    if ((ctx->rs_ctx = info->rs_alloc_func()) == NULL)
        return (MBEDTLS_ERR_PK_ALLOC_FAILED);

    ctx->pk_info = info;

    return (0);
}
#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */

/*
 * Verify a signature (restartable)
 */
int mbedtls_pk_verify_restartable(
    mbedtls_pk_context* ctx,
    mbedtls_md_type_t md_alg,
    const unsigned char* hash,
    size_t hash_len,
    const unsigned char* sig,
    size_t sig_len,
    mbedtls_pk_restart_ctx* rs_ctx)
{
    PK_VALIDATE_RET(ctx != NULL);
    PK_VALIDATE_RET((md_alg == MBEDTLS_MD_NONE && hash_len == 0) || hash != NULL);
    PK_VALIDATE_RET(sig != NULL);

    if (ctx->pk_info == NULL || pk_hashlen_helper(md_alg, &hash_len) != 0)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);

#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
    /* optimization: use non-restartable version if restart disabled */
    if (rs_ctx != NULL && mbedtls_ecp_restart_is_enabled() && ctx->pk_info->verify_rs_func != NULL) {
        int ret;

        if ((ret = pk_restart_setup(rs_ctx, ctx->pk_info)) != 0)
            return (ret);

        ret = ctx->pk_info->verify_rs_func(ctx->pk_ctx, md_alg, hash, hash_len, sig, sig_len, rs_ctx->rs_ctx);

        if (ret != MBEDTLS_ERR_ECP_IN_PROGRESS)
            mbedtls_pk_restart_free(rs_ctx);

        return (ret);
    }
#else  /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
    (void)rs_ctx;
#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */

    if (ctx->pk_info->verify_func == NULL)
        return (MBEDTLS_ERR_PK_TYPE_MISMATCH);

    return (ctx->pk_info->verify_func(ctx->pk_ctx, md_alg, hash, hash_len, sig, sig_len));
}

/*
 * Verify a signature
 */
int mbedtls_pk_verify(
    mbedtls_pk_context* ctx, mbedtls_md_type_t md_alg, const unsigned char* hash, size_t hash_len, const unsigned char* sig, size_t sig_len)
{
    return (mbedtls_pk_verify_restartable(ctx, md_alg, hash, hash_len, sig, sig_len, NULL));
}

/*
 * Verify a signature with options
 */
int mbedtls_pk_verify_ext(
    mbedtls_pk_type_t type,
    const void* options,
    mbedtls_pk_context* ctx,
    mbedtls_md_type_t md_alg,
    const unsigned char* hash,
    size_t hash_len,
    const unsigned char* sig,
    size_t sig_len)
{
    PK_VALIDATE_RET(ctx != NULL);
    PK_VALIDATE_RET((md_alg == MBEDTLS_MD_NONE && hash_len == 0) || hash != NULL);
    PK_VALIDATE_RET(sig != NULL);

    if (ctx->pk_info == NULL)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);

    if (!mbedtls_pk_can_do(ctx, type))
        return (MBEDTLS_ERR_PK_TYPE_MISMATCH);

    if (type == MBEDTLS_PK_RSASSA_PSS) {
#if defined(MBEDTLS_RSA_C) && defined(MBEDTLS_PKCS1_V21)
        int ret;
        const mbedtls_pk_rsassa_pss_options* pss_opts;

#if SIZE_MAX > UINT_MAX
        if (md_alg == MBEDTLS_MD_NONE && UINT_MAX < hash_len)
            return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
#endif /* SIZE_MAX > UINT_MAX */

        if (options == NULL)
            return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);

        pss_opts = (const mbedtls_pk_rsassa_pss_options*)options;

        if (sig_len < mbedtls_pk_get_len(ctx))
            return (MBEDTLS_ERR_RSA_VERIFY_FAILED);

        ret = mbedtls_rsa_rsassa_pss_verify_ext(
            mbedtls_pk_rsa(*ctx), NULL, NULL, MBEDTLS_RSA_PUBLIC, md_alg, (unsigned int)hash_len, hash, pss_opts->mgf1_hash_id,
            pss_opts->expected_salt_len, sig);
        if (ret != 0)
            return (ret);

        if (sig_len > mbedtls_pk_get_len(ctx))
            return (MBEDTLS_ERR_PK_SIG_LEN_MISMATCH);

        return (0);
#else
        return (MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE);
#endif /* MBEDTLS_RSA_C && MBEDTLS_PKCS1_V21 */
    }

    /* General case: no options */
    if (options != NULL)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);

    return (mbedtls_pk_verify(ctx, md_alg, hash, hash_len, sig, sig_len));
}

/*
 * Make a signature (restartable)
 */
int mbedtls_pk_sign_restartable(
    mbedtls_pk_context* ctx,
    mbedtls_md_type_t md_alg,
    const unsigned char* hash,
    size_t hash_len,
    unsigned char* sig,
    size_t* sig_len,
    int (*f_rng)(void*, unsigned char*, size_t),
    void* p_rng,
    mbedtls_pk_restart_ctx* rs_ctx)
{
    PK_VALIDATE_RET(ctx != NULL);
    PK_VALIDATE_RET((md_alg == MBEDTLS_MD_NONE && hash_len == 0) || hash != NULL);
    PK_VALIDATE_RET(sig != NULL);

    if (ctx->pk_info == NULL || pk_hashlen_helper(md_alg, &hash_len) != 0)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);

#if defined(MBEDTLS_ECDSA_C) && defined(MBEDTLS_ECP_RESTARTABLE)
    /* optimization: use non-restartable version if restart disabled */
    if (rs_ctx != NULL && mbedtls_ecp_restart_is_enabled() && ctx->pk_info->sign_rs_func != NULL) {
        int ret;

        if ((ret = pk_restart_setup(rs_ctx, ctx->pk_info)) != 0)
            return (ret);

        ret = ctx->pk_info->sign_rs_func(ctx->pk_ctx, md_alg, hash, hash_len, sig, sig_len, f_rng, p_rng, rs_ctx->rs_ctx);

        if (ret != MBEDTLS_ERR_ECP_IN_PROGRESS)
            mbedtls_pk_restart_free(rs_ctx);

        return (ret);
    }
#else  /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */
    (void)rs_ctx;
#endif /* MBEDTLS_ECDSA_C && MBEDTLS_ECP_RESTARTABLE */

    if (ctx->pk_info->sign_func == NULL)
        return (MBEDTLS_ERR_PK_TYPE_MISMATCH);

    return (ctx->pk_info->sign_func(ctx->pk_ctx, md_alg, hash, hash_len, sig, sig_len, f_rng, p_rng));
}

/*
 * Make a signature
 */
int mbedtls_pk_sign(
    mbedtls_pk_context* ctx,
    mbedtls_md_type_t md_alg,
    const unsigned char* hash,
    size_t hash_len,
    unsigned char* sig,
    size_t* sig_len,
    int (*f_rng)(void*, unsigned char*, size_t),
    void* p_rng)
{
    return (mbedtls_pk_sign_restartable(ctx, md_alg, hash, hash_len, sig, sig_len, f_rng, p_rng, NULL));
}

/*
 * Decrypt message
 */
int mbedtls_pk_decrypt(
    mbedtls_pk_context* ctx,
    const unsigned char* input,
    size_t ilen,
    unsigned char* output,
    size_t* olen,
    size_t osize,
    int (*f_rng)(void*, unsigned char*, size_t),
    void* p_rng)
{
    PK_VALIDATE_RET(ctx != NULL);
    PK_VALIDATE_RET(input != NULL || ilen == 0);
    PK_VALIDATE_RET(output != NULL || osize == 0);
    PK_VALIDATE_RET(olen != NULL);

    if (ctx->pk_info == NULL)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);

    if (ctx->pk_info->decrypt_func == NULL)
        return (MBEDTLS_ERR_PK_TYPE_MISMATCH);

    return (ctx->pk_info->decrypt_func(ctx->pk_ctx, input, ilen, output, olen, osize, f_rng, p_rng));
}

/*
 * Encrypt message
 */
int mbedtls_pk_encrypt(
    mbedtls_pk_context* ctx,
    const unsigned char* input,
    size_t ilen,
    unsigned char* output,
    size_t* olen,
    size_t osize,
    int (*f_rng)(void*, unsigned char*, size_t),
    void* p_rng)
{
    PK_VALIDATE_RET(ctx != NULL);
    PK_VALIDATE_RET(input != NULL || ilen == 0);
    PK_VALIDATE_RET(output != NULL || osize == 0);
    PK_VALIDATE_RET(olen != NULL);

    if (ctx->pk_info == NULL)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);

    if (ctx->pk_info->encrypt_func == NULL)
        return (MBEDTLS_ERR_PK_TYPE_MISMATCH);

    return (ctx->pk_info->encrypt_func(ctx->pk_ctx, input, ilen, output, olen, osize, f_rng, p_rng));
}

/*
 * Check public-private key pair
 */
int mbedtls_pk_check_pair(const mbedtls_pk_context* pub, const mbedtls_pk_context* prv)
{
    PK_VALIDATE_RET(pub != NULL);
    PK_VALIDATE_RET(prv != NULL);

    if (pub->pk_info == NULL || prv->pk_info == NULL || prv->pk_info->check_pair_func == NULL) {
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);
    }

    if (prv->pk_info->type == MBEDTLS_PK_RSA_ALT) {
        if (pub->pk_info->type != MBEDTLS_PK_RSA)
            return (MBEDTLS_ERR_PK_TYPE_MISMATCH);
    } else {
        if (pub->pk_info != prv->pk_info)
            return (MBEDTLS_ERR_PK_TYPE_MISMATCH);
    }

    return (prv->pk_info->check_pair_func(pub->pk_ctx, prv->pk_ctx));
}

/*
 * Get key size in bits
 */
size_t mbedtls_pk_get_bitlen(const mbedtls_pk_context* ctx)
{
    /* For backward compatibility, accept NULL or a context that
     * isn't set up yet, and return a fake value that should be safe. */
    if (ctx == NULL || ctx->pk_info == NULL)
        return (0);

    return (ctx->pk_info->get_bitlen(ctx->pk_ctx));
}

/*
 * Export debug information
 */
int mbedtls_pk_debug(const mbedtls_pk_context* ctx, mbedtls_pk_debug_item* items)
{
    PK_VALIDATE_RET(ctx != NULL);
    if (ctx->pk_info == NULL)
        return (MBEDTLS_ERR_PK_BAD_INPUT_DATA);

    if (ctx->pk_info->debug_func == NULL)
        return (MBEDTLS_ERR_PK_TYPE_MISMATCH);

    ctx->pk_info->debug_func(ctx->pk_ctx, items);
    return (0);
}

/*
 * Access the PK type name
 */
const char* mbedtls_pk_get_name(const mbedtls_pk_context* ctx)
{
    if (ctx == NULL || ctx->pk_info == NULL)
        return ("invalid PK");

    return (ctx->pk_info->name);
}

/*
 * Access the PK type
 */
mbedtls_pk_type_t mbedtls_pk_get_type(const mbedtls_pk_context* ctx)
{
    if (ctx == NULL || ctx->pk_info == NULL)
        return (MBEDTLS_PK_NONE);

    return (ctx->pk_info->type);
}

#endif /* MBEDTLS_PK_C */
